Millions of Shi'ite Muslims gathered at shrines and mosques for Ashura, which falls on the tenth day of the holy month of Muharram. The festival commemorates the slaying of Prophet Muhammad's grandson Hussein at the battle of Kerbala in AD 680.

Shi'ites beat their heads and chests with chains and knives, and gash their heads with swords to show their grief and echo the suffering of Imam Hussein.

Afghan Shi'ite Muslim men flagellate themselves with chains and knives in KabulReutersChains with blood-stained blades on them are seen during commemorations of Ashura in KabulAFPAfghan Shi'ite devotees beat themselves with chains and blades in KabulAFPPakistani Shi'ite Muslims flagellate themselves during an Ashura procession in PeshawarAFP

In Iraq's holy city of Kerbala, hundreds of thousands of pilgrims gathered outside the Shrine of Imam Hussein chanting: "Hussein, Hussein, Hussein."

This is the first time Ashura has been observed since Sunni extremists — who view Shi'ites as apostates deserving of death — seized much of northern and western Iraq.

Iraqis gather in front of the shrine of Imam Hussein, one of Shi'ite Islam's most revered figures - during the Ashura commemorations that mark his killing, in KerbalaAFPIraqi Shi'ite men in Baghdad reenact the Battle of Kerbala, which resulted in the killing of Imam Hussein, the grandson of the Prophet Muhammad, by the army of the Caliph Yazid in 680 AD, the formative event in Shi'ite IslamAFPAn Iraqi Shi'ite girl watches the reenactment of the Battle of Kerbala as part of Ashura commemorations in BaghdadAFP

Countries with sizeable Shi'ite communities such as Afghanistan, Iran, Pakistan, and Syria also commemorate the day.

Shi'ite Muslim boys run over burning coals in Yangon, Burma.GettyA man picks a razor up from the floor after flagellating himself during a ceremony for Ashura at a mosque in Yangon, BurmaReutersA man is sprayed with rose water as he flagellates himself in Mumbai, IndiaReutersKashmiri Shi'ite Muslims beat their chests during a procession in SrinagarReutersLebanese Hezbollah supporters take part in a religious procession to mark Ashura in BeirutReutersBahraini Shi'ite Muslim take part in a ceremony marking Ashura in the village of Sanabis, west of ManamaAFPA young Iraqi Shi'ite Muslim boy flagellates himself during a ceremony marking Ashura in BasraAFPShi'ite Muslims take part in a traditional event to mark Ashura in the northern Iraqi city of NajafAFPShi'ite Muslims perform with fire during celebrations of Ashura in Najaf, IraqReutersA Shi'ite Muslim has his child's head gashed with a knife during a procession to mark Ashura in Mumbai. The festival, which falls on the 10th day of the Islamic month of Muharram, commemorates the death of Imam Hussein, grandson of Prophet MuhammadReutersAn Afghan Shi'ite Muslim flagellates himself during an Ashura procession in Kabul. The festival, which falls on the 10th day of the Islamic month of Muharram, commemorates the death of Imam Hussein, grandson of Prophet Muhammad, who was killed in the seventh century battle of KerbalaReutersPakistani Shi'ite Muslims flagellate themselves during a religious procession in IslamabadAFPA Pakistani Shi'ite Muslim man receives stitches after flagellating himself during a procession in IslamabadReuters